Pasteurella multocida pneumonia with molecular evidence of zoonotic transmission

We report the case of a patient with pneumonia caused by Pasteurella multocida (P. multocida). An 83-year-old woman admitted for bronchiectasis, productive cough, and a high fever was found in chest radiography on admission to have a new infiltrative shadow in the left lower lung field. Chest computed tomography indicated bilateral bronchiectasis and an infiltrative lingular shadow. P. multocida was isolated from sputum samples. Biapenem and minocycline therapy ameliorated symptoms. Pulsed-field gel electrophoresis (PFGE) showed that the clinical isolate recovered was identical to the P. multocida isolate recovered from the pharyngeal swab specimen culture obtained from the patient's dog. Several years later, P. multocida subsp. gallicida isolates were recovered from human sputum and a canine pharyngeal swab specimen. PFGE confirmed these isolates to be identical and PFGE band patterns were identical to those of previous P. multocida isolates. These findings suggest that P. multocida was transmitted from the patient's dog to the patient and underscore the need to inform susceptible hosts at risk of contracting zoonotic agents about basic hygiene rules for keeping pets. PFGE data strengthened the evidence of zoonotic transmission of P. multocida through casual contact in a patient with a respiratory infection caused by this organism. PFGE should prove useful in both epidemiological tracing and preventing pasteurellosis and clarifying its pathology. Case reports of respiratory infections including pneumonia caused by P. multocida are increasing in humans, and P. multocida respiratory infections appear to occur mostly in patients with chronic respiratory disease. A history of pet exposure, even without bites or scratches, should alert the physician to P. multocida as a potential respiratory pathogen.